1. Field of the Invention
This invention pertains to a two-piece grommet which is used to attach panels to one another. In particular, the grommet allows travel in one plane to compensate for thermal expansion and contraction between the panels.
2. Description of the Prior Art
In the prior art, it is known to use grommets to attach a first panel to a second panel. While sliding grommets are likewise known in the prior art to allow for sliding between the panels, these prior art grommets have been deficient in that the strip torque has been variable as the metal stamping process used to manufacture these grommets has typically not had good thread engagement characteristics. Similarly, these prior art sliding grommets have sometimes been deficient with respect to their resistance to rotation. Furthermore, these prior art sliding grommets typically have not provided good sealing characteristics with respect to water, dust and sound.
Some examples of prior art include U.S. Pat. No. 5,738,476 entitled xe2x80x9cFastenerxe2x80x9d issued on Apr. 14, 1998 to Assimakopoulos;
U.S. Pat. No. 5,536,125 entitled xe2x80x9cSliding Two-Piece Fastenerxe2x80x9d issued on Jul. 16, 1996 to Gaw, Jr.; U.S. Pat. No. 5,533,237 entitled xe2x80x9cGrommet Fastener Assembly for Automobilesxe2x80x9d issued on Jul. 9, 1996 to Higgins; U.S. Pat. No. 5,484,175 entitled xe2x80x9cCabinet Lock and Method for Using Samexe2x80x9d issued on Jan. 16, 1996 to Teich et al.; U.S. Pat. No. 5,429,467 entitled xe2x80x9cHigh Torque Screw and Grommet Fastener Assemblyxe2x80x9d issued on Jul. 4, 1995 to Gugle et al.; U.S. Pat. No. 5,129,768 entitled xe2x80x9cSliding Grommetxe2x80x9d issued on Jul. 14, 1992 to Hoyle et al.; U.S. Pat. No. 4,971,500 entitled xe2x80x9cEnclosed Plastic Screw Grommetxe2x80x9d issued on Nov. 20, 1990 to Benoit et al.; U.S. Pat. No. 4,865,505 entitled xe2x80x9cStructure for Mounting Automobile Interior Upholstering Materialxe2x80x9d issued on Sep. 12, 1989 to Okada; U.S. Pat. No. 4,729,606 entitled xe2x80x9cApparatus for Mounting a Wheel Capxe2x80x9d issued on Mar. 8, 1988 to Narita et al.; and U.S. Pat. No. 4,043,579 entitled xe2x80x9cElastomeric Bumper Securing Press Fit Clipxe2x80x9d issued on Aug. 23, 1977 to Meyer.
It is therefore an object of the present invention to provide a sliding grommet for attaching two panels wherein the grommet has increased resistance to rotation.
It is therefore a further object of the present invention to provide a sliding grommet for attaching to panels wherein the grommet has a relatively uniform strip torque.
It is therefore a still further object of the present invention to provide a sliding grommet for attaching two panels wherein the grommet provides increased sealing capabilities with respect to moisture, dust and sound.
It is therefore a final object of the present invention to provide a sliding grommet which achieves the above objects with a relatively low manufacturing cost.
These and other objects are attained by providing a two-piece grommet comprising a base which detent engages a rectangular aperture on a first panel. The two-piece grommet further includes a slider which includes an extended screw boss with a square cross section which is slidably engaged within a rectangular slot formed in the base. A second panel is engaged to the sliding grommet by a screw which extends through the second panel and is engaged within the extended screw boss.
The screw boss extends into the rectangular slot in the base and is slidably engaged therein. This reduces rotation between the slider and the base. Similarly, extending the screw boss into the body increases the strength of the screw boss, increases the strip torque and reduces the variability of the strip torque.
The resulting fit between the base and the slider, with reduced or eliminated exposed apertures, increases the sealing with respect to moisture, dust and sound. This sealing can be further improved by providing a foam or rubber washer between the base and the first panel.
Moreover, the resulting design is relatively inexpensive to manufacture.